In virtually all aspects of life, one of the most common positions that a person finds himself or herself in is being seated in a chair. Whether behind the desk at work, in an automobile or airplane, or simply relaxing at home, a significant portion of each day is spent in a chair. Unfortunately, however, most of the chairs in use today are not ergonomically designed. As a result, users of these chairs often experience significant discomfort after extended periods of use.
Research has shown that one of the most important factors in the overall comfort of a chair is the proper positioning and alignment of the armrests. Generally speaking, a person sitting in a chair without armrests is more likely to experience a higher degree of pain, skeletal, and muscular problems over time, especially in the neck, shoulder, and upper arm region, than a person sitting in a chair with armrests. However, the mere presence of armrests does not necessarily eliminate the discomfort discussed above, because the armrests may not be properly positioned or aligned for a particular user of the chair. In other words, for a given chair design, the proper positioning and alignment of the armrests may differ for different users of the chair. Every user is likely to have a unique combination of the position and alignment of the armrests that provides the optimum comfort.
Therefore, adjustable chair armrests are well known and widely used in an attempt to improve the overall comfort level of today's chairs. An exemplary embodiment of such an adjustable chair armrest is disclosed in U.S. Pat. No. 5,590,934 to Gibbs. An adjustable chair armrest is provided that is rotatable about a vertical axis. A positioning plate of the armrest includes a plurality of positioning holes that define a series of potential positions or orientations of the armrest.
Although such an adjustable armrest provides greater flexibility than a fixed or stationary armrest, there are still significant disadvantages associated with the armrest disclosed in Gibbs that are typical of the problems associated with preexisting adjustable chair armrests in general. For example, the armrest in Gibbs is only capable of assuming a select few positions through a portion of its rotation. As with other preexisting adjustable chair armrests, a finite range of positions and orientations of the armrest cannot guarantee the optimum level of comfort for all users of the chair. Moreover, the armrest disclosed in Gibbs, and other preexisting adjustable chair armrests, only contains a single axis of rotation, which naturally limits the range of possible positions of the armrest, and therefore, limits the overall level of comfort available from the armrest. While the use of multiple axes of rotation is known in some areas, such as in various equipment associated with donating blood, the design of this equipment is poorly suited for use in armrest assemblies.
Consequently, as a result of these and other disadvantages associated with preexisting armrests, a need exists for an improved adjustable chair armrest.